This invention relates to pinball games in general and to methods and apparatus for actuating flippers in particular. As is well known in the pinball art, flippers are pivotally-mounted members positioned on the game playfield to enable players to hold, and/or redirect steel game balls while in play on the game playing field. A flipper must be capable of delivering sufficient force to propel a steel ball under dynamic conditions, that is, while both the ball and flipper are in motion as well as supporting the ball to position it for a shot. In this latter "static" state, the flipper is activated or energized, but neither the flipper nor ball are in motion.
Traditionally, flippers have been actuated by the player operating a flipper switch located on the side of the pinball cabinet. When closed, the switch completes an electric circuit to a solenoid mechanism which is linked to the flipper. Movement of the solenoid rotates the flipper, causing it to propel the ball, or hold it on the flipper. When the flipper button is released, the solenoid is deactivated.
Examples of flipper solenoids and circuits are shown in prior art U.S. Pat. Nos. 4,790,536 to Deger and 4,384,716 to Powers and in application Ser. Number 579,782 to Coldebella assigned to the present assignee. In Deger, a solenoid having two parallel coils are employed. Both coils are used to achieve the first power level, while only one coil is used for holding purposes. In Powers, a coil is fully activated for the power stroke and then power to the solenoid is decreased by phase control in the manner of a light dimmer.
In the Coldebella application, the flipper assembly disclosed in Deger is augmented with "slip detect" and timer circuitry to reenergize the flipper in the event that the ball striking the flipper causes it to slip from its fully energized position.
All of these disclosures are concerned with enhancing the operation of the flipper to improve player appeal. In particular, they increase the force of the flipper, maintain the flipper in an extended position and prevent slippage, while at the same time preventing overheating of the solenoid which would occur if full power was applied to the solenoid for long periods. In each case, however, the flipper is directly controlled by the player through operation of a flipper switch.
According to the present invention, it is desired to interpose the game microprocessor between the player and the flippers. This provides a number of advantages not found in the prior art. First, the processor can monitor the flipper coil operation and, if necessary, intercede to prevent overheating. This also improves flipper power by reducing power loss since only low voltage signal lines run from the player operated flipper buttons to the processor.
Controlling the flippers with the game processor provides additional advantages however, including the possibility of permitting the processor to activate one or more flippers independently of the player. This can be used as a reward to the player for making a difficult shot, to assist an inexperienced player or simply to create a unique playfield attraction. More specifically, the game processor can be programmed to attempt to make a difficult flipper shot using feedback from playfield sensors (switches). The processor can "learn" and improve its aim much to the amazement and satisfaction of game players.
Accordingly, it is an object of the present invention to provide an automatic flipper control circuit in which the game micro-processor controls actuation of the flippers to enhance player appeal.
It is a further object of the invention to provide apparatus in which game software is able to control flipper actuation, therefore to permit the player and/or the game software to enable or disable all or selected ones of the flippers.
These and other objects of the invention will become apparent to those skilled in the art from the detailed description of the invention provided below.